Computer displays can be used for a wide variety of tasks, some of which involve long periods of users viewing a display. This can lead to eye strain and other physiological effects if viewing considerations are not taken into account. Some display functions that make extended viewing of the screen hard are apparent, such as a flickering screen, reading green text on a bright pink background, etc. However, there are some others that are more subtle.
With reflective displays, ambient light impinges on the display surface and is reflected off of a back plane of the display while some of the impinging light is absorbed by display elements, thus creating the image being displayed (which can be an image comprising text, pixels, lines, etc.). With emissive displays, the display supplies the light source and the display elements block some of the light, thus creating the image being displayed. Viewing a sheet of paper having an image thereon is more like reflective displays, in that the display (the paper) does not generate its own light, but reflects ambient light. Physiologically, many viewers will perceive a sheet of white paper with black lettering as being white regardless of the color of the ambient light (within limits). In some cases, it might be desirable to have similar effects with emissive displays.
Appendix A provides an example of program code.
Appendix B provides an example of a set of calculations.
Appendix C provides another example of program code.